Spray nozzles are utilized in many areas where a spray of fluid is required, for example: tank and drum washing; metal washing; foam control; asphalt spraying; vehicle washing; and dish washing. For tank and drum washing, one of the more popular forms of spray nozzles is the self-excited or self-driven rotating spray nozzle assembly. Such a nozzle assembly is secured to an end of a supply pipe and the device is inserted into the vessel to be cleaned either by means of entryways specifically designed for the purpose of cleaning the vessel, or by utilizing existing vessel entryways. The nozzle assembly comprises a fixed or stationary stem for mounting to the supply pipe, and a rotating nozzle body. A bore or passageway extends through the stationary mounting element to outlets that feed the rotating nozzle body rotatably mounted on an outlet end of the stem. Rotating spray nozzle assemblies generally have spray outlets, or outlet orifices, that are provided in pairs opposite one another and at an angle to the axis of rotation. This provides driving forces to rotate the nozzle body. The rotation is intended to distribute the spray over a specific area within the vessel to be cleaned. This area may include a portion, or the complete interior, of the vessel to be cleaned. Exemplary of such rotating spray nozzles is the disclosure of the present inventor's prior U.S. Pat. No. 5,316,218.
As exemplified in the aforesaid U.S. Pat. No. 5,326,218, rotating spray nozzles are characterized by multi-part construction, with the nozzle body being captured on the stem by means of a separate screw threadingly engaging a correspondingly threaded bore provided in the stem. Furthermore, a conical washer is provided, either integral with the screw or as a separate element therefrom. In a second embodiment disclosed in that patent, a retaining clip is provided. The clip has a head, a bifurcated shaft and angled engagement surfaces. The angled engagement surfaces are resiliently pressed inwards during insertion of the retaining clip into a bore provided through the stem and, when fully inserted, they spring outwards to engage shoulders inside the stem.